Wealden sandstones

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Occurrence of the Deister, Nesselberg, Osterwald and (partly) Süntelsandsteins
Welfenschloss Hanover built partly with Wealden sandstone from the Nesselberg
Pied Piper House built with Wealden sandstone from the Süntel
New town hall of Hanover built from Deister sandstone

The Wealden sandstones , also known as Süntel- , Deister- , Nesselberg- , Osterwald- and Bückebergsandstein (today Obernkirchener Sandstein ) come from surveys in northern Germany, from the Deister , Nesselberge , Süntel , Osterwald and Bückeberg . This sandstone group originated in the Lower Cretaceous , more precisely the Berriasium and were previously assigned to the facies of the " Wealden " (forest clay). In 2008 there were two quarries in which Wealden sandstones are quarried. On the one hand the Bückeberge in Obernkirchen the quarry of Obernkirchener sandstone. On the other hand, the Wesling company quarry in Münchehagen , which does not, however, produce any larger stone.

Origin and occurrence

The distribution of the Wealden sandstones extends from the elevations of the Deister and the Stemmer Berg in the north , the Rehburg Mountains in the southwest of the Steinhuder Meer and the Bückeberge to the Harrl in the west, the Süntel near Hameln , the Nesselberg and the Osterwald .

These mountain ranges are formed from brackish water , slate and sandstone , in which coal seams are also embedded. The thickness of the layers is different and the clayey and sandy layers alternate and it is 6 to 7 meters in the Rehburg Mountains, in Harrl and in the Bückeberg the minable deposit is 14 to 20 meters high, in Stemmer Berg around 100 meters, in the Süntel the height is 200 to 300 meters and in the Deister the thickness decreases sharply. When drilling deep in the Steinbachtal, thicknesses of 340 m were found, and further down the valley at Flegessen, 390 m.

Mining sites

The mining sites on the ridge of the Bückeberg are around Obernkirchen , those of the Deister are around Barsinghausen , Egestorf and Bredenbeck . On the Süntel the quarries were around Hamelspringe and Welliehausen and on the Nesselberge near Altenhagen and in the Osterwald at Osterwald. In the west of the Weser, the Wealden sandstones occur on the northern edge of the Wiehengebirge near Bohmte , in the Teutoburg Forest near Borgholzhausen , Eppendorf and Wellingholzhausen and near Peine near Abbensen .

Mineral composition and rock properties

The proportions of these sandstones are: quartz 79 to 82 percent, rock fragments 18 to 20 percent, heavy metals up to 2 percent. These sandstones have rounded quartz grains that are predominantly quartzitic and only rarely clay or limestone. The grain is fine, and now and then there are coarser and very rarely conglomerate layers. The color is mostly yellowish, gray-white, yellowish-gray. Individual layers are brownish, yellow and spotted. The coloring results from limonite , an iron-containing rock. There are also carbonaceous particles. Most valued is a Wealden sandstone, the Obernkirchen sandstone, because it is weather-resistant, has an even and fine grain, which makes it ideal for stone carving work but also for weatherproof building blocks.

Although the other Wealden sandstones do not achieve the quality of the Obernkirchen sandstone, they are solid and weather-resistant rocks.

Use and structures

The Wealden sandstone was used for solid buildings, masonry, stone , stair and floor coverings, facades and monuments and stone carving work. For larger construction projects, stone and rough blocks were often obtained from various quarries:

Dinosaur tracks

In the sandstone layers of the Lower Saxony Berrias, traces of large dinosaurs were discovered when the stone was extracted. The first documented finds date from around 1840. The traces of large sauropods found in Münchehagen in 1980 , which are now protected as a natural monument of dinosaur tracks in Münchehagen, became famous . In 2004, further tracks of various types of dinosaurs were discovered in the neighboring quarry. Excavations are carried out there by a cooperation between the Dinosaur Park Münchehagen , the State Museum Hanover , the University of Göttingen and other partners. In 2007 the dinosaur tracks of Obernkirchen were discovered in this context .

See also

literature

  • W. Dienemann and O. Burre: The usable rocks of Germany and their deposits with the exception of coal, ores and salts , Enke-Verlag, Stuttgart 1929, p. 288ff.
  • Wolf-Dieter Grimm: picture atlas of important monument rocks of the Federal Republic of Germany . Edited by the Bavarian State Office for Monument Preservation, Lipp-Verlag, Munich 1990, ISBN 3-87490-535-7 , rock no.119.
  • Jahn J. Hornung, Annina Böhme, Torsten van der Lubbe, Mike Reich and Annette Richter: Vertebrate tracksites in the Obernkirchen Sandstone (late Berriasian, Early Cretaceous) of northwest Germany Paläontologische Zeitschrift, September 2012, Volume 86, Issue 3, p. 231 -267, download: http://link.springer.com/article/10.1007%2Fs12542-012-0131-7

Individual evidence

  1. ^ Helga Knoke: Forest and settlement in the Süntel ; P. 10